Oil Pan

A number of special tools are required for this procedure. The working clearance is very tight. The transaxle mounts are loosened so the engine can be repositioned. Without the support of the transaxle mounts, the engine must be suspended from above in such a way the vehicle can still be raised for the undercar work. The factory engine support fixture has legs which extend across the engine compartment and rest on the shock towers with additional legs resting on the radiator support. Other engine support fixtures are similar in design. It may be possible to rent a similar device locally. Use care if using any type of substitute. Damage to the vehicle and/or personal injury is possible if the powertrain shifts or is dislodged from the vehicle.

Fig. An engine support fixture like this supports the engine so the mounts can be loosened for undercar engine work-typical for front wheel drive vehicles

Disconnect the negative battery cable.

Remove the hood.

Remove the engine mount struts from the engine.

Without disconnecting the refrigerant lines, remove the air conditioning compressor mounting bolts and set the compressor aside.

Remove the right engine mount strut bracket from the engine.

Install a suitable engine support fixture. Verify that the engine will be safely supported.

Raise and safely support the vehicle.

Disconnect the three-way catalytic converter pipe from the right side (rear) exhaust manifold.

Drain the engine oil into a suitable container.

Detach the oil level sensor wiring harness connector from the sensor in the oil pan.

Remove the starter motor. Please see Section 2.

Remove the transaxle brace from the oil pan.

Remove the lower transaxle mount nuts.

Remove the lower engine mount nuts.

Raise the engine using the adjustable hooks on the engine support fixture, to gain access for oil pan removal.

Fig. This special wrench is recommended by GM for removing and installing the right side (rear) oil pan side bolts. A box wrench with a slight offset may also be used

There are bolts that go through the side of the oil pan and thread into the main bearing caps. GM recommends their special tool J 39505 be used on the right side (rear) oil pan side bolts, to reach up in the narrow area between the engine oil pan and the transaxle case to remove these bolts. This special tool is also used at assembly so the bolts can be properly tightened. Use care is using a substitute wrench to remove the right side (rear) oil pan side bolts.

Remove the left side (front) oil pan side bolts.

Remove the oil pan side rail mounting bolts.

Remove the oil pan from the vehicle.

To install:

Clean all parts well. If the engine has high mileage, evaluate changing the oil pump at this time. Please see the procedure in this section. Make sure the oil pan gasket rails and the engine gasket sealing surfaces are clean.

Apply a small amount of sealer GM #1234579, or equivalent, on either side of the rear main bearing cap, where the seal surface on the cap meets the engine block. Press sealant into the gap with a putty knife.

Install the oil pan gasket, then position the oil pan to the engine. Hand-start a few side rail bolts. Install, then finger-tighten all side rail bolts. Then torque to 18 ft. lbs. (25 Nm).

Install the left side (front) oil pan side bolts. Torque to 37 ft. lbs. (50 Nm).

Install the right side (rear) oil pan side bolts, using special tool J 39505 or equivalent. Torque to 37 ft. lbs. (50 Nm).

Using the adjustable hooks on the engine support fixture, lower the engine enough so the lower transaxle mount nuts can be installed. Also install the lower engine mount nuts and the transaxle brace to the oil pan.

Install the remaining components in the reverse order of the removal process. Refill the engine with clean engine oil. A filter change is also recommended.

3.4L (VIN X) Engine

WARNING

This is a complicated procedure. In this procedure, the subframe that supports the entire powertrain is loosened and removed so the engine oil pan can be removed. This is not a job for the inexperienced or ill-equipped. Be very sure that the oil pan really needs to be removed before attempting this procedure. Be very sure of the lifting and jacking equipment you have available before attempting this procedure or the vehicle could be damaged and you could be injured. Without the support of the subframe, the engine must be suspended from above in such a way the vehicle can still be raised for the undercar work. The factory engine support fixture has legs which extend across the engine compartment and rest on the shock towers with additional legs resting on the radiator support. Other engine support fixtures are similar in design. It may be possible to rent a similar device locally. Use care if using any type of substitute. Extensive and expensive damage to the vehicle and its major components and/or personal injury is possible if the powertrain drops from the vehicle. In addition, the factory specifies that whenever frame to body bolts are loosened or removed, they must be replaced with new bolts and retainers. Procure the bolts before beginning this procedure. Failure to replace frame-to-body bolts and retainers may result in damage to the frame, powertrain or suspension.

Disconnect the negative battery cable.

Remove the hood assembly.

Remove the air cleaner duct.

Drain the coolant and remove the coolant recovery reservoir.

Install the engine support fixture. Verify that the engine and transaxle assembly will be safely supported when the subframe is removed.

With the engine support fixture in place, raise and safely support the vehicle.

Remove the power steering rack and pinion steering gear retaining bolts. Without disconnecting the fluid lines, hang the steering gear on the body.

Remove the right and left lower ball joint nuts. Separate the lower ball joints from the control arms. Please see Section 8.

Remove the power steering cooler line clamps at the frame.

Remove the engine mount nuts at the subframe. Support the subframe.

Have an assistant hold the subframe or use a suitable lifting/jacking device to safely support the subframe while removing the body mount bolts. Remove the subframe retaining bolts. Discard the bolts. They must be replaced with new bolts upon assembly. Carefully lower the subframe with both the lower control arms and the stabilizer shaft attached. Work the subframe downward toward the rear of the vehicle.

Remove the oil filter, the engine oil cooler and the oil level sensor.

Remove the flywheel cover and the starter motor. Please see Section 2.

Apply sealer GM #12345739 to the tabs of the oil pan gasket that insert next to the rear main bearing cap notches. Install the new oil pan gasket and position the pan to the engine. Hand start a few retaining bolts.

If the rubber frame isolators were removed, lubricate with rubber lube GM #1051717 or equivalent at installation. Failure to lubricate may prevent proper seating of insulators in the frame. Make sure the insulators are completely sealed against the frame.

Using the lifting/jacking device and an assistant, raise the frame until it frame contacts the body. Install new replacement body bolts, but do not tighten yet, observing the following:

Alignment pins are required. Do not remove the alignment pins until all of the body mount bolts are torqued to specifications. The alignment pins must be kept perpendicular to the frame. The right side mounts (nearest the alignment pins) should be tightened first, to maintain correct front wheel alignment. Align the frame by inserting two 0.74 inch (19mm) diameter by 8.0 inch (200mm) long pins in the alignment holes on the right side of the frame.

Proper clamping by the mount depends on clean and dry surfaces. If the frame isolator bolt does not screw in smoothly, it may be necessary to run a tap through the cage nut in the body to remove foreign material. Take care that the tap does not punch through the underbody. If the cage nut cannot be used, the cage nut retainer spot welds will have to be chiseled away with air chisel, the cage nut replaced and the retainer welded back into its original location. Clean and prime the area with catalyzed primer to protect the area from corrosion.

Torque the four new frame isolator bolts to 133 ft. lbs. (180 Nm). Do not over-tighten the body mounts; a collapsed spacer or stripped bolt may result. Tighten in the following manner:

RH Rear, first

RH Front, second

LH Rear, third

LH Front, fourth

Install the engine mount nuts at the subframe.

Connect the three-way catalytic convert pipe to the exhaust manifold.

Install the power steering cooler line clamps at the frame.

Connect the ball joints to the control arms. Please see Section 8.

CAUTION

When installing the intermediate shaft, make sure the shaft is seated prior to pinch bolt installation. If the pinch bolt is inserted into the coupling before shaft installation, the two mating shafts may disengage, with a loss of steering.

Connect the intermediate steering shaft to the rack and pinion steering assembly stub shaft. Verify that the two shafts are properly coupled. Insert the pinch bolt and torque carefully to 35 ft. lbs. (47 Nm).

Install the power steering rack and pinion steering gear assembly on the steering gear mounts. Please see Section 8.

Clean all parts well. Make sure the oil pan gasket rails, the engine front cover, the rear main bearing cap and the engine gasket sealing surfaces are clean. Use care. The engine crankcase is aluminum. Do not scratch or gouge the sealing surfaces. Clean all threaded holes.

If changing out the oil pan with a service replacement part, move the oil level switch to the new oil pan. Tighten the sensor bolt to 80 inch lbs. (9 Nm).

There is a rather specific installation sequence for the oil pan and transaxle brace bolts. Carefully follow the next steps.

Using a new gasket, install the oil pan to the engine and hand start a few oil pan bolts. With the pan properly positioned, install and finger-tighten all of the oil pan bolts.

To ensure proper mounting of the transaxle, align the cast boss on the rear of the oil pan so it is flush with the rear of the cylinder block face. Use a straightedge to check the pan alignment from the rear of the block face to the bolt boss on the oil pan.

Press the forward part of the oil pan against the transaxle brace. Be sure to keep the rear of the oil pan flush with the rear face of the cylinder block.

Torque the transaxle brace-to-oil pan bolts to 18 ft. lbs. (25 Nm).

Keep the rear of the oil pan flush with the rear cylinder block and tighten the oil pan retaining bolts. Use the sequence illustrated, working from the center outward, similar to installing an intake manifold or cylinder head. Torque the oil pan bolts to 18 ft. lbs. (25 Nm).

Tighten the remaining transaxle brace bolts to the transaxle.

Connect the oil level sensor to the harness, install the oil drain plug and install a new oil filter.

Lower the vehicle.

Refill with clean engine oil and inspect for leaks.

3.8L Engine

CAUTION

A special engine support fixture as well as a transaxle jack are required for this procedure. The reason is that the engine mount brackets wrap around the oil pan and must be removed for access to the oil pan. This means the engine must be suspended from above in such a way the vehicle can still be raised for the undercar work. The factory engine support fixture has legs which extend across the engine compartment and rest on the shock towers with additional legs resting on the radiator support. Other engine support fixtures are similar in design. It may be possible to rent a similar device locally. Use care if using any type of substitute. Damage to the vehicle and/or personal injury is possible if the powertrain shifts or is dislodged from the vehicle.

Disconnect the negative battery cable.

Remove the wish bone-shaped engine mount struts from the engine

Install an engine support fixture to safely support the weight of the engine when the engine mount brackets are removed.

Raise and safely support the vehicle.

Disconnect the front exhaust pipe the manifold.

Remove the right front tire and right inner fender splash shield.

Drain the engine oil and remove the oil filter.

Verify that the engine support fixture is in place and engine properly and safely supported. Remove the U-shaped metal engine mount brackets from the front of the engine and the rear of the engine.

Remove the flywheel cover.

Position a transaxle jack under the transaxle, to raise the engine by lifting the transaxle.

Remove the oil level sensor, located in the oil pan, before the oil pan is removed. The sensor may be damaged if the oil pan is removed first.

Remove the oil pan retaining bolts and lower the oil pan.

Fig. Engine oil pan arrangement-3.8L engines

To install:

Clean all parts well. Make sure the oil pan gasket rails, the engine front cover, the rear main bearing cap and the engine gasket sealing surfaces are clean. Clean all threaded holes. Some engines may use a "windage tray" which is a sheetmetal shield designed to keep oil from the spinning crankshaft. This reduces oil foaming and helps cut drag from the oil on the crankshaft. This sheetmetal shield may have a formed-in-place seal that acts as an oil pan gasket.

Prepare a few cleaned engine oil pan bolts with GM # 12345382, or equivalent thread-locking compound. Install the oil pan gasket (or sheetmetal shield, if equipped), and install the oil pan. Hand start a few of the thread-locking compound treated oil pan bolts. With the pan secure, install the remainder of the oil pan bolts, all of which should be treated with the thread-locking compound. Tighten the bolts to just 125 inch lbs. (14 Nm). DO NOT OVERTIGHTEN THE OIL PAN BOLTS. Overtightening the oil pan bolts can damage the oil pan, resulting in an oil leak.

Install the oil pan level sensor after the oil pan has been installed. Tighten the sensor to 15 ft. lbs. (20 Nm). Attach the connector.